I created this baskets for the Back to Hogwarts R4 Swap. He stands 15” tall and is 12” wide. And can hold a ton of stuff! I will say if you whip up this pattern, you will get a workout after holding 2 strands of super bulky while crocheting this.

do you starch it to make it stand up, or are the stitches really tight?

No starching, it stands up on its own. The patterns calls for holding several strands together (alternatively doing what I did and using 2 strands of super-bulky Lion Brand Wool-Ease Thick & Quick), which gives it enough body to stand on it own.

I guess you have to use super bulky yarn to make it stiff enough to stand up on its own.

I did use super-bulky Lion Brand Wool-Ease Thick & Quick, 2 strands held together. You could also use 4 strands of bulky yarn to achieve the same effect (in fact, that is what the pattern materials cal for).